Move incubation branding requirements into handbook

Submitted by Wayne Beaton @wbeaton

Link to original bug (#488421)

Description

The handbook already includes much of the content in the "Project Phases" section. This should be pulled out into its own section.

https://www.eclipse.org/projects/handbook/#starting-project-phases

The wiki page should be scavenged for any other germane information and retired.

https://wiki.eclipse.org/Development_Resources/HOWTO/Conforming_Incubation_Branding